The function of Ethereum public key
Ethereum is an open source public blockchain platform with smart contract function. It provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency ether (also known as "Ethereum")
The token on theblockchain is called ether, and the code is eth. It can be traded in many foreign exchange markets of cryptocurrency, and it is also the medium used to pay transaction fees and computing services on Ethereum
the concept of Ethereum was first proposed by vitalik buterin, a programmer, from 2013 to 2014, inspired by bitcoin, with the general meaning of "next generation cryptocurrency and decentralized application platform", and began to develop through ICO crowdfunding in 2014. As of February 2018, Ethernet is the second highest cryptocurrency in market value, second only to bitcoin
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Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
suppose I find two strings of numbers, one is 1 * and the other is 2 *. I like the number 2 * and I will keep it. I won't tell you (private key). Then I will tell you that 1 * is my public key
I have a file that I can't let others see, so I use 1 * to encrypt it. Someone else found this file, but he didn't know that 2 * was the private key for decryption, so he couldn't decrypt it. Only I could decrypt it with
string 2 *, which is my private key. So I can protect the data
my good friend x encrypts the character a with my public key 1 * and then it becomes B, which is put on the Internet. Other people steal this file, but they can't open it, because they don't know that 2 * is my private key,
only I can decrypt it and get a after decryption. In this way, we can transmit encrypted data<
Second, private key signature
If I encrypt a piece of data with the private key (of course, only I can encrypt with the private key, because only I know 2 * is my private key), as a result, all people will see my content, because they all know that
my public key is 1 *, then what is the use of this encryption
but my good friend x said that someone pretended to write to him. What shall I do? I encrypt the content of the letter I want to send with my private key 2 * and send it to X. then I tell him to decrypt it to see if it is C. He decrypted it with my public key 1 * and found that it was c
at this time, he will think that the data that can be decrypted with my public key must be encrypted with my private key. Only I know my private key, so he can confirm that it's really something I sent
in this way, we can confirm the identity of the sender. This process is called digital signature. Of course, the specific process is a little more complicated. The purpose of encrypting data with private key is digital signature
summary: public key and private key are paired, they decrypt each other
public key encryption and private key decryption
private key digital signature, public key verification.
encryption is to encrypt data, so that even if illegal users get encrypted data, they can not get the correct data content, so data encryption can protect data and prevent monitoring attacks. It focuses on the security of data. Identity authentication is used to judge the authenticity of an identity. After the identity is confirmed, the system can give different permissions according to different identities. It focuses on the authenticity of users. The emphasis of the two is different< Secondly, we need to understand the concept and function of public key and private key
in the modern cryptosystem, encryption and decryption use different keys (public key), that is, asymmetric key cryptosystem. Each communication party needs two keys, namely public key and private key, which can be used to encrypt and decrypt each other. The public key is public and does not need to be kept secret, while the private key is held by the indivial himself and must be kept and kept secret. Principle of public key and private key: one public key corresponds to one private key. Key pair, let everyone know is the public key, do not tell you, only their own know, is the private key. If one of the keys is used to encrypt data, only the corresponding key can be decrypted. If one of the keys can be used to decrypt data, the data must be encrypted by the corresponding key.
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" Public key & quot; Explanation in reference book
1. Encryption key in public key cryptosystem
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& quot; Public key & quot; The explanation in academic literature
1. Traditional key refers to the same key used for encryption and decryption, while public key refers to one key used for encryption and another key used for decryption, and another key cannot be obtained with one key. RSA encryption algorithm is a kind of public key algorithm and can be used for digital visa, To confirm the identity of the other party
source of literature
2. RAS is a factorization encryption algorithm, which converts the integer prime into two groups of ciphers. One group is used for encryption, which is called public key. The other group is used for decryption, which is known only by the information decryptor, which is called private key
source of literature
3. The key is a large integer, A participant publishes a key in a public database, which is called a public key, and uses another key as a secret key. A message encoded with one key can be decoded with another key. For example, if the sender encodes the message with a secret key, the receiver can decode it with the sender's public key Asymmetric encryption technology means that users use two different interdependent keys, one is called public key, the other is called private key, which is used to encrypt and decrypt information
literature sources
5, (5) (n, e) or E is called "public key." (n, d) or D is called "private key". The private key (n, d) of RSA algorithm is used to encrypt the developer, and the public key (n, d) is used to encrypt the developer, E) (E = 65537) it is used for decryption in the verification part of user software. If the pair of keys are changed regularly, it will bring difficulty to the cracker.
source of literature
6, 2.2 security mechanism based on public key system. The biggest feature of public key cryptography algorithm [2] is to separate the encryption and decryption capabilities by using two related keys, one of which is public, It is called public key
document source
7,6) (E, n) is called public key. 7) (D, n) is called secret key, or vice versa. For plaintext m, encryption with public key (E, n) can get ciphertext C. C = memodn. For ciphertext C, decryption with private key (D, n) can get plaintext m
document source
8, It is called "public key". The other key is private by the key holder, which is called "private key". The message is encrypted with the public key, and only the corresponding private key holder can decrypt it. Therefore, the message becomes the secret of the private key holder
source
9. In this way, everyone has a pair of keys, one of which is called public key, The other one is called private key. When there is a need to transmit data on the Internet, the public key can be spread out in a certain way
literature sources
10. One of them is published publicly, which is called public key, and the other one is kept secretly by the user, which is called private key. The sender uses the public key to encrypt the data, Asymmetric encryption is an encryption key, which is different from decryption key. Encryption key is called public key publicly. Decryption key is called private key only by oneself. Its frame length is 10ms, which is composed of two subframes, preview 5ms and processing delay 35ms (12) Extract the "version" information in the certificate. 2.1 use RSA encryption algorithm to generate key pair. RSA encryption algorithm [1] is a public key encryption algorithm, which uses a pair of keys to encrypt and decrypt data. A key is called public key,
for example: public key is the public key (password) --- Everyone knows the password: 123456
private key is the private key (password) --- but I know the password: confidentiality
give you a million bank card, (public key and private key) can you withdraw money?
The principle of public key system is: user a has a pair of key pairs, which are divided into public key and private key. This pair of key pairs is unique and is obtained by factoring a huge prime number. When the information encrypted by public key can only be decrypted by the private key matched with it, and vice versa, the information encrypted by private key can only be decrypted by public key. In this way, after a generates a key pair from the authentication system, a keeps its private key and publishes the public key. When a user B wants to communicate with a and wants to ensure the data security, he can use a's public key to encrypt the information and then send the ciphertext to A. therefore, in this world, only a's private key can decrypt the ciphertext, thus ensuring the information security
in fact, information encryption is only one of the purposes of public key system. It also has the purpose of signing information to prevent the information publisher from repudiating and being modified by a third party. Why can this mechanism realize this function? Very simple, or use the "public key encryption, only the private key can solve; Private key encryption, only the public key can solve the problem. For example: user a signs (encrypts) the information he sends out with his private key, and then sends it out. Later, he finds that the information he publishes is not good for him, so he doesn't admit that he sent the information, but he can't deny it, because the information has his private key signature. Then, he uses his public key to verify the information, This information must be sent by a, because only the information obtained from the private key signature used by a can be solved by this public key. If a still admits that he sent the message, there is only one possibility, that is, his private key has been stolen
now that we know the principle of public key mechanism, what is its use? The above examples are quite common. In our daily work, there are some places where the public key mechanism is used. Someone may have used the key disk, which is similar to a U disk. Generally, it provides a USB interface and uses the public key mechanism. When we initialize the key disk on a computer, it will generate a pair of key pairs and store the public key on the computer, The private key is stored on the key disk. When a user wants to authenticate the identity of a system, he can only insert the key disk, and complete the authentication process of the user through the principle of public and private key encryption and decryption, without entering the account number and password
obviously, both symmetric cryptography and public key cryptography need to ensure the security of the key. The difference lies in the management and distribution of the key. In symmetric cryptography, there must be a reliable means to tell the decryptor the encryption key (which is also the decryption key); In the public key cryptosystem, this is not necessary. The decryptor only needs to ensure the confidentiality of his private key, and the public key is public to both the encryptor and the cryptanalyzer, so there is no need to consider using a reliable channel for password distribution. This greatly reces the difficulty of key management and key distribution
encryption and decryption: the sender uses the public key of the receiver to encrypt the plaintext to be sent, while the receiver uses its own private key to decrypt it. The public key is opposite to the private key, and any one of them is the public key, and the other one is the private key, Then asymmetric encryption technology is used to encrypt symmetric key, namely digital envelope technology.
signature and verification: the sender uses a special hash algorithm to generate a fixed length digest from the plaintext, and then uses its own private key to encrypt the digest. This process is called signature. The receiver uses
the sender's public key to decrypt the encrypted digest to get result a, and then hashes the plaintext to generate digest B. finally, a and B are compared. This method can not only ensure that the identity of the sender is not
deniable, but also ensure that the data will not be tampered in the process of transmission< First of all, we need to distinguish their concepts:
encryption and authentication
first, we need to distinguish the two basic concepts of encryption and authentication
encryption is to encrypt data, so that even if illegal users get encrypted data, they can not get the correct data content, so data encryption can protect data and prevent monitoring attacks. It focuses on the security of data. Identity authentication is used to judge the authenticity of an identity. After the identity is confirmed, the system can give different permissions according to different identities. It focuses on the authenticity of users. The emphasis of the two is different
public key and private key
secondly, we need to understand the concept and function of public key and private key
in the modern cryptosystem, encryption and decryption use different keys (public key), that is, asymmetric key cryptosystem. Each communication party needs two keys, namely public key and private key, which can be used to encrypt and decrypt each other. The public key is public and does not need to be kept secret, while the private key is held by the indivial himself and must be kept and kept secret
principle of public key and private key:
one public key corresponds to one private key
in the key pair, what we all know is the public key, but what we only know is the private key
if one of the keys is used to encrypt data, only the corresponding key can be decrypted
if one of the keys can be used to decrypt data, the data must be encrypted by the corresponding key
the main application of asymmetric key cryptography is public key encryption and public key authentication, and the process of public key encryption is different from that of public key authentication. I will explain the difference in detail below
Case Description:
for example, if there are two users, Alice and Bob, Alice wants to send a piece of plaintext to Bob through double key encryption technology, and Bob has a pair of public key and private key, then the encryption and decryption process is as follows:
Bob sends his public key to Alice
Alice encrypts her message with Bob's public key and sends it to Bob
Bob decrypts Alice's message with his private key< How can Bob identify whether Alice is real or fake? We just need to use the opposite method to the above example.
Alice uses her private key to encrypt the file and sign it
Alice sends the signed file to Bob
Bob decrypts the file with Alice's public key to verify the signature
through examples, you should know something about it!